A known variable valve timing control devices is disclosed in Japanese Patent Laid-open published as JP2001-3716A2. The disclosed variable valve timing control device includes a housing member integrally rotating with a crankshaft of an internal combustion engine, a rotor member assembled to the housing member so as to be rotatable relative thereto, including vane portions forming an advanced angle chamber and a retarded angle chamber within the housing member, and integrally rotating with the camshaft. The variable valve timing control device also includes a fluid pressure circuit for controlling operation oil to be supplied to or discharged from the advanced angle chamber or the retarded angle chamber. The variable valve timing control device further includes a lock mechanism including a lock groove provided at the rotor member and a lock member being freely projecting/retreating and provided at the housing member. The relative rotation between the housing member and the rotor member is restricted when the lock member is projected and engaged with the lock groove. On the other hand, the relative rotation between the housing member and the rotor member is permitted when the lock member is retracted and disengaged from the lock groove.
According to such known variable valve timing control device, the lock groove is formed at inner side in the radial direction of the rotor member, and a bolt used for attaching the rotor member to the camshaft is provided at the center portion of the rotor member. Further, an oil path is also provided at the center portion of the rotor member for communicative connecting the advanced angle chamber and an oil pressure source, and the retarded angle chamber and the oil pressure source.
In such configuration, a seal portion is short in radial direction of the housing member and the rotor portion, so that the lock member may be improperly operated because the operation oil applied to the lock member is leaked from the seal portion.
A need exists for a variable valve timing control system to include a lock mechanism preventing the improper operation of the lock mechanism due to the leaked operation oil by sealing between the housing member and the rotor member.